Caption: Laboratory microchip. Coloured scanning electron micrograph (SEM) of the surface of a microfluidic microchip, a type of microelectromechanical system (MEMS). This is used in laboratory analysis, and is commonly called a 'lab on a chip'. Samples and analytical chemicals mix in the chambers and flow through the microchannels. The small size of these channels (typically less than 1 millimetre across) allows many properties to be measured, including fluid viscosity, pH, enzyme reaction kinetics, the molecular diffusion co-efficient, number of cells, and protein properties. Manufacturerd by microTEC, Duisburg, Germany. Magnification: x67 when printed 10 centimetres wide.